This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Localizing mRNA into distinct compartment before translation is a commonmechanism to distribute protein inside the cell. This contributessignificantly in early oocyte development and is critical for cell polarityestablishment and maintenance. In budding yeast, ASH1 mRNA is loacalized intothe daughter cell and this localization plays a critical role in mating typeswitch. Several genes, She1 to She5, has been identified to function in thispathway, and they encode proteins including motor protein, mRNA bindingprotein, adapter, myosin regulating molecule as well as cytoskeletonorganizing molecule. To understand the function of these genes in mRNAlocalization, and the organization and regulation of the mRNA localizationfactors in yeast, I am combining biochemistry, cell biology and x-raycrystallography to study the molecular structure of these protein andinvestigate their detailed function.